refactor: flatten CaidoCapability into direct wiring

The custom ``Capability`` subclass was 207 LoC bundling four tiny
concerns (env-var injection, tool exposure, system-prompt block,
healthcheck) — and three of them were dead code: the SDK's
``SandboxRunConfig`` doesn't accept capabilities, so
``process_manifest``, ``tools()``, and ``instructions()`` were never
called. Only ``bind()`` ran, because we invoked it manually.

Replace each piece with the obvious direct equivalent:

- **Env vars**: inject ``http_proxy`` / ``https_proxy`` / ``ALL_PROXY``
  directly into the manifest in ``session_manager.create_or_reuse``.
  This *also fixes a latent bug* — the proxy env vars in
  ``CaidoCapability.process_manifest`` weren't being applied to live
  containers, so shelled-out HTTP traffic from terminal/python tools
  wasn't actually flowing through Caido.
- **Tool exposure**: add the seven Caido tools (``list_requests``,
  ``view_request``, ``send_request``, ``repeat_request``,
  ``scope_rules``, ``list_sitemap``, ``view_sitemap_entry``) to
  ``_BASE_TOOLS`` in ``agents/factory.py`` like every other sandbox
  tool. They were already defined in ``tools/proxy/tools.py``.
- **Healthcheck**: ``entry.py`` now ``await``s
  ``wait_for_http_ready`` + ``wait_for_tcp_ready`` inline after
  ``session_manager.create_or_reuse`` returns, before any agent runs.
  No more capability state, ``configure_host_ports`` plumbing, or
  ``on_agent_start`` await-the-task indirection.
- **Instructions block**: dropped. The seven proxy tools' docstrings
  cover the HTTPQL syntax and usage already; the duplicate prompt
  fragment was overhead.

Cascade cleanups:
- Drop ``caido_capability`` from the agent context (was passed to
  every ``make_agent_context`` call but only used by the now-deleted
  ``on_agent_start`` await).
- Strip the capability await branch from
  ``StrixOrchestrationHooks.on_agent_start``; that hook now does only
  the ``tracer.agents`` mirroring it always should have.
- Drop the ``capability`` key from the session bundle.
- Drop ``strix/sandbox/caido_capability.py`` — entire file (207 LoC).
- Drop the per-file ruff ignore for the deleted file.

mypy clean on every touched file. Net -217 LoC.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

pyproject.toml

@@ -249,9 +249,6 @@ ignore = [
 "strix/tools/proxy/tools.py" = ["TC002"]
 "strix/tools/agents_graph/tools.py" = ["TC002"]
 "strix/agents/factory.py" = ["TC002"]
-# CaidoCapability uses agents.tool.Tool at runtime — pydantic Field
-# annotations and the cached _CAIDO_TOOLS tuple need it eagerly.
-"strix/sandbox/caido_capability.py" = ["TC002"]
 # Entry point: ``Path`` is used at runtime by the typing of the
 # session_manager call; importing under TYPE_CHECKING would defer
 # resolution past where mypy needs it. ``_build_root_task`` legitimately